When I was a sophomore in high school I played slot receiver on the junior varsity football team. One week, when we were playing a big rival, several of our starters were moved up to varsity, leaving 13 players on the junior varsity. We called ourselves the Baker's Dozen.
As you might expect, when you're playing with only 13 players, including the backup quarterback (who was the starting running back), the backup running back (to replace the one now playing quarterback), and a couple of backup linemen, the game is not going to go well. And it didn't.
During the first half, the left guard blew out his knee. We didn't have any backup linemen, so I had to move to guard for the remainder of the game. I weighed 120 pounds, so I was a bit over-matched.
Later, after being punched by the guy he was blocking several times (in full view of the referee) our left tackle finally punched him back and was thrown out of the game (as was the guy on the other team). One of our wide receivers had to take his place, and he weighed less than I did. And unlike me, he had never played on the line before. He also didn't know any of the blocking assignments, so before each play he would ask me who he should block. I would point to one of the players lined up near him and say, "Block that guy."
Since we had two lineman on the left side who were much smaller than the opposing side, and since our quarterback was a runner and not a thrower, our entire offense consisted of running plays to the right side. We were very easy to stop. I'm not sure if we got a first down the rest of the game.
And since all 11 starters on offense also had to play defense, we were very easy to score on. In fact, the opposing team kept their starters in the entire game, running up the score. They were attempting to score 70 or more points.
But we held them to 63.
EPILOGUE: The following year, when I was on the varsity football team, this rival team was favored by 14 points when we played them. We won by 29.